A social worker is assigned to make the Simpson family functional after they get arrested for fighting while playing Monopoly. He helps them learn how to work together and function as a family. The moment is ruined when, Ginger and Amber, the barmaids who married Homer and Flanders while they were drunk in "Viva Ned Flanders", arrive at the Simpsons' home, which outrages Marge.

After Homer and Bart's model rocket damages the church, Mr. Burns makes a deal to commercialize the church in return for paying for the damages. Lisa becomes disgusted at what the church has become, so she decides to find a new religion suitable for her. She eventually converts to Buddhism, causing Marge to fear for Lisa's soul.

Springfield is officially declared the World's Fattest Town after an attempt to break a world record lands everyone on top of a truck scale. Out of embarrassment and disgust, Marge goes on a crusade against the local sugar corporation. However, when sugar is banned, Homer, Bart, Mr. Burns and Apu start bootlegging sugar.

Homer develops a snoring problem, so Marge decides to spend a night with her sisters Patty and Selma. After a night of drinking, Marge sees a news report about her ex-prom date Artie Ziff, who is now very wealthy, and decides to send him an e-mail. Artie is still obsessed with Marge, so he offers the Simpsons $1 million in exchange for Marge spending a weekend with him.

A jaw injury from colliding with a new town statue turns Homer into a better listener while recuperating with his jaws wired shut, but once the wires come off, Homer does not go back to being loud and obnoxious and Marge becomes starved for thrills.

Bart befriends Rainer Wolfcastle's daughter Greta. She has a crush on Bart, but he does not seem to realize it and eventually stops seeing her. Seeking revenge, Greta begins dating Bart's best friend Milhouse, which causes Bart to start missing her. She leaves for Toronto with her father, and Bart convinces his family to follow them there.

While running away from a vicious dog, Bart meets Buck McCoy, a former Western film star. Bart begins hanging out with him and starts to idolize him. Bart wants to help McCoy stage a comeback, so he convinces all of the kids in town to become interested in the Wild West. McCoy appears on the Krusty the Clown Show, but the comeback flops when Buck begins drinking again and injures Krusty the Clown.

When Homer gets a notice from the library that he has a book of classic tales that is years overdue, he finds it on the shelf and reads three stories: The Odyssey (where Homer and his bar buddies try to get home after fighting the Trojans), Joan of Arc (where Lisa leads the French against the English with the help of God), and Hamlet (where Bart tries to kill Moe after Moe kills Homer in order to marry Marge).

Grampa falls in love with Zelda, a woman who has an interest in men who can drive. He decides to get his driver's license back, but is ignorant to Homer and Marge's concerns that she is only using him for his car.

When Homer gets the family's telephone service cut off for refusing to pay for calls made to Rio de Janeiro, Brazil, Lisa confesses that she was the one who called Rio after sponsoring an orphan who goes missing. She convinces the family to travel to Brazil to look for him. However, once there, they have no luck finding him, and Homer is kidnapped.

Homer is prescribed medicinal marijuana after getting pecked in the eyes by a murder of crows. While his family and friends worry about the drug altering his personality, Homer becomes Mr. Burns's vice president after cracking up at Burns's antiquated jokes.

In this clip show episode, Homer is honored at a Friars' Club Roast. A number of characters show up to roast him, but the celebrating is interrupted by Kang and Kodos, who say that humanity will be judged based on Homer's experiences.

Inspired by a cartoonist who speaks at the school as part of a career day assembly, Bart creates a comic book series based on Homer and his anger problems, which turns into a popular Internet cartoon series called Angry Dad. Homer finds out about this and is at first outraged, but after talking to his family, he decides to try to become a less angry person.

Homer and Marge discover that Apu is having an affair with the Squishee delivery lady at the Kwik-E-Mart. They decide to keep Apu's wife Manjula from finding out about it. However, she eventually learns of Apu's affair by watching store security tapes. She throws Apu out of the house and decides to file for divorce, but soon realizes that she misses him.

Lisa tries to fit in with two college students by lying about her age. She finds that the college atmosphere is perfect for her, but her lie is soon discovered and she is shunned by her fellow elementary school students. Meanwhile, Bart is diagnosed with a weakened immune system after getting bitten by a Chinese mosquito and must live in a plastic, germ-free bubble.

While faced with community service for abusing an endangered insect, Homer begins assisting an elderly woman named Mrs. Bellamy. One night, Mrs. Bellamy is murdered, and Homer and Marge are accused of committing the crime.

Homer starts a security company with Lenny and Carl after the police are ineffective during a blackout, and eventually Mayor Quimby decides to have them replace the police. Homer finds that he excels at the job, but then he runs afoul of mob boss Fat Tony, who threatens Homer with death unless he leaves town.

Thinking Homer does not find her attractive anymore, Marge decides to get liposuction, but instead receives breast implants. She becomes adored by many of the men in Springfield, and becomes a spokesmodel for trade shows. Meanwhile, Bart and Milhouse try to imitate a stunt they saw on an episode of Batman that guest stars Krusty the Clown. When the stunt ends badly, media watchdog groups blame Krusty, forcing the clown to make his show more safety-conscious and less fun.

The 13th Treehouse of Horror episode, consisting of three self-contained segments.

Send in the Clones – Homer buys a hammock that can produce clones of himself. He creates numerous clones to help him around the house, but they soon overrun Springfield.

The Fright to Creep and Scare Harms – Lisa petitions the town to get rid of their firearms after discovering the gravestone of a young man named William Bonney who died from gun violence. However, Lisa soon discovers that William Bonney is the real name of Western outlaw Billy the Kid, whose ghost, along with the ghosts of other infamous criminals, takes over the defenseless town.

The Island of Dr. Hibbert – Dr. Hibbert invites the citizens of Springfield to his island resort, where he turns them into animals.

The Simpsons buy a satellite television, which Bart spends so much time watching that he does not study for an important achievement test. He scores so low that Principal Skinner demotes him to third grade, while Lisa does so well that she is moved up to third grade. The two are placed in the same class and become rivals. During a trip to Capital City, they get separated from their class and are forced to help each other in order to find their classmates.

The Simpson family has to find temporary residence while their house is fumigated for termites. When they run out of options, they decide to become contestants on a reality show where families live in the manner that people did in 1895. The family is initially miserable, but slowly adapt to their new life, which causes the show to lose ratings. The producers decide to try to boost viewers by dumping the house in a river and forcing the family to survive in the wilderness. However, the Simpsons find a bunch of rejects from other reality shows and they attack the producers.

A drunken Homer appears on the show Taxicab Conversations and rants about how awful his life as a husband and father is. Although his family is at first outraged, they realise that they do somewhat burden him and decide to make up for it by sending him to a Rock 'n Roll Fantasy Camp where he mingles with rock stars, including Mick Jagger and Keith Richards. The rock stars ask Homer to help out at a concert and, expecting that he will be allowed to perform, he accepts. Actually, they want him to test the microphones; however, a humiliated Homer grabs a guitar and starts playing.